G1000 Reference Guide - SkyHoppers

SECTION 11 – ABNORMALOPERATION11.6 DEAD RECKONINGWhile in Enroute or Oceanic phase of flight, if theG1000 detects an invalid GPS solution or is unable tocalculate a GPS position, the system will automaticallyrevert to Dead Reckoning (DR) Mode. In DR Mode,the G1000 uses its last-known position combined withcontinuously updated airspeed and heading data (whenavailable) to calculate and display the aircraft’s currentestimated position.through DR while there is no heading and/or airspeeddata available should not be used for navigation.DR Mode is inherently less accurate than thestandard GPS/WAAS Mode due to the lack of satellitemeasurements needed to determine a position. Changesin wind speed and/or wind direction will compound therelative inaccuracy of DR Mode. Because of this degradedaccuracy, the crew must maintain position awareness usingother navigation equipment until GPS-derived positiondata is restored.NOTE: Dead Reckoning Mode will only function inEnroute (ENR) or Oceanic (OCN) phase of flight.In all other phases, an invalid GPS solution willproduce a ‘NO GPS POSITION’ annunciation onthe map and the G1000 will stop navigating inGPS Mode.DR Mode is indicated on the G1000 by the appearanceof the letters ‘DR’ superimposed in yellow over the ‘ownaircraft’ symbol as shown in Figure 11-4. In addition, ‘DR’will be prominently displayed, also in yellow, on the HSIslightly above and to the right of the aircraft symbol on theCDI as shown in Figure 11-4. Also, the CDI deviation baris removed from the display. Lastly, but at the same time, a‘GPS NAV LOST’ alert message will appear on the PFD.Normal navigation using GPS/WAAS source datawill resume automatically once a valid GPS solution isrestored.It is important to note that estimated navigationdata supplied by the G1000 in DR Mode may becomeincreasingly unreliable and must not be used as a solemeans of navigation. If while in DR Mode airspeed and/orheading data is also lost or not available, the DR functionmay not be capable of accurately tracking your estimatedposition and, consequently, the system may display a paththat is different than the actual movement of the aircraft.Estimated position information displayed by the G1000CDI ‘DR’ Indication on PFDSymbolic Aircraft(Map pages and Inset Map)Figure 11-4 Dead Reckoning IndicationsAs a result of operating in DR Mode, all GPS-deriveddata will be computed based upon an estimated positionand will be displayed as yellow text on the display todenote degraded navigation source information. Thisdata includes the following:• Navigation Status Box fields except Active Leg, TAS,and DTK• GPS Bearing Pointer• Wind data and pointers in the Wind Data Box onthe PFD and MFD• Track Bug• All Bearing Pointer Distances• Active Flight Plan distances, bearings, and ETEvaluesAlso, while the G1000 is in DR Mode, the autopilot willnot couple to GPS, and both TAWS and Terrain Proximity190-00384-07 Rev. AGarmin G1000 Cockpit Reference Guide for the Cessna Nav III11-3